Unlimited arity curried computation

unlim-arity.ts

const aux = (f: (a,b) => number, acc: number) => 
  (n?: number) => (n !== undefined) ? aux(f, f(acc, n)) : acc;

const add = (a, b) => a + b;
const mul = (a, b) => a * b;

const sum = aux(add, 0);
const product = aux(mul, 1);

const sum1 = sum(2)(3)(5)(); //10
const prod1 = product(2)(3)(5)(); // 30